Terminal apparatus, base station apparatus, and integrated circuit

ABSTRACT

A terminal apparatus, a base station apparatus, a communication method, an integrated circuit, and a radio communication system are provided that enable a base station apparatus and a terminal apparatus to determine parameters relating to an uplink reference signal and efficiently communicate with each other. A terminal apparatus that transmits a demodulation reference signal, the terminal apparatus comprising: means for receiving a cell-specific parameter used for enabling or disabling a sequence group hopping, means for a user-equipment-specific parameter used for disabling the sequence group hopping, and means for generating a sequence of the demodulation reference signal on the basis of the enabled or disabled sequence group hopping, wherein, in a case that a transmission on the physical uplink shared channel corresponding to a downlink control information format to which CRC parity bits scrambled by a temporary C-RNTI are attached, the sequence group hopping is enabled or disabled on the basis of the cell-specific parameter.

TECHNICAL FIELD

The present invention relates to a terminal apparatus, a base stationapparatus, a communication method, an integrated circuit, and a radiocommunication system.

BACKGROUND ART

In a radio communication system such as LTE (Long-Term Evolution) orLTE-A (LTE-Advanced) developed by the 3GPP (Third Generation PartnershipProject) or WiMAX (Worldwide Interoperability for Microwave Access)developed by the IEEE (Institute of Electrical and ElectronicsEngineers), a base station and a terminal each include one or aplurality of transmission and reception antennas and can realizehigh-speed data communication using, for example, a MIMO (multiple inputmultiple output) technique.

Here, in radio communication systems, it is being examined to supportMU-MIMO (multiple user MIMO), in which a plurality of terminals performspatial multiplexing using the same frequency and time resources. Inaddition, it is being examined to support a CoMP (cooperativemultipoint) communication scheme, in which a plurality of base stationscooperatively perform interference coordination. For example, a radiocommunication system is being examined that adopts a heterogeneousnetwork deployment (HetNet) realized by a macro base station having widecoverage and an RRH (remote radio head) having coverage narrower thanthat of the macro base station.

In such a radio communication system, if uplink reference signalstransmitted by a plurality of terminals have the same characteristics,interference occurs. Here, for example, a method has been proposed fororthogonalizing demodulation reference signals (DMRSs) transmitted bythe plurality of terminals to one another in order to reduce or suppressinterference between the demodulation reference signals (NPL 1).

CITATION LIST Non Patent Literature

NPL 1: DMRS enhancements for UL CoMP; 3GPP TSG RAN WG1 meeting #68R1-120277, Feb. 6-10, 2012.

SUMMARY OF INVENTION Technical Problem

With respect to radio communication systems, however, there has been nodescription regarding a specific procedure used by a base station and aterminal for determining parameters relating to an uplink referencesignal. That is, there has been no description regarding how a basestation and a terminal determine the parameters relating to the uplinkreference signal and communicate with each other.

The present invention has been established in view of the above problem,and an object thereof is to provide a base station apparatus, a terminalapparatus, a communication method, an integrated circuit, and acommunication system that enable a base station and a terminal todetermine parameters relating to an uplink reference signal andefficiently communicate with each other.

Solution to Problem

(1) In order to achieve the above object, the present invention takesthe following measures. That is, a terminal apparatus that transmits ademodulation reference signal associated with a physical uplink sharedchannel to a base station apparatus, the terminal apparatus comprising:means for receiving, from the base station apparatus, a cell-specificparameter used for enabling or disabling a sequence group hopping, meansfor receiving, from the base station apparatus, auser-equipment-specific parameter used for disabling the sequence grouphopping, and means for generating a sequence of the demodulationreference signal on the basis of the enabled or disabled sequence grouphopping, wherein, in a case that a transmission on the physical uplinkshared channel corresponding to a downlink control information format towhich CRC parity bits scrambled by a temporary C-RNTI are attached isperformed in a random access procedure, the sequence group hopping isenabled or disabled on the basis of the cell-specific parameterregardless of the user-equipment-specific parameter.

(2) In addition, a terminal apparatus that transmits a demodulationreference signal associated with a physical uplink shared channel to abase station apparatus, the terminal apparatus comprising: means forreceiving, from the base station apparatus, a cell-specific parameterused for enabling or disabling a sequence group hopping, means forreceiving, from the base station apparatus, a user-equipment-specificparameter used for disabling the sequence group hopping, and means forgenerating a sequence of the demodulation reference signal on the basisof the enabled or disabled sequence group hopping, wherein, in a casethat a transmission of a Message 3 on the physical uplink shared channelcorresponding to a random access response grant is performed in a randomaccess procedure, the sequence group hopping is enabled or disabled onthe basis of the cell-specific parameter regardless of theuser-equipment-specific parameter.

(3) In addition, a terminal apparatus that transmits a demodulationreference signal associated with a physical uplink shared channel to abase station apparatus, the terminal apparatus comprising; means forreceiving, from the base station apparatus, a cell-specific parameterused for enabling or disabling a sequence group hopping, means forreceiving, from the base station apparatus, a user-equipment-specificparameter used for disabling the sequence group hopping, and means forgenerating a sequence of the demodulation reference signal on the basisof the enabled or disabled sequence group hopping, wherein the sequencegroup hopping is disabled on the basis of the user-equipment-specificparameter regardless of the cell-specific parameter, unless atransmission of a Message 3 is on the physical uplink shared channelscorresponding to a downlink control information format to which CRCparity bits scrambled by a temporary C-RNTI are attached or on thephysical uplink shared channel corresponding to a random access responsegrant is performed in a random access procedure.

(4) In addition, a base station apparatus that receives a demodulationreference signal associated with a physical uplink shared channel from aterminal apparatus, a sequence of the demodulation reference signalbeing generated on the basis of enabled or disabled sequence grouphopping, the base station apparatus comprising: means for transmitting,to the terminal apparatus, a cell-specific parameter used for enablingor disabling the sequence group hopping, and means for transmitting, tothe terminal apparatus, a user-equipment-specific parameter used fordisabling the sequence group hopping, wherein, in a case that a downlinkcontrol information format to which CRC parity bits scrambled by atemporary C-RNTI are attached is used for scheduling for a transmissionon the physical uplink shared channel in a random access procedure, thesequence group hopping is enabled or disabled on the basis of thecell-specific parameter regardless of the user-equipment-specificparameter.

(5) In addition, a base station apparatus that receives a demodulationreference signal associated with a physical uplink shared channel from aterminal apparatus, a sequence of the demodulation reference signalbeing generated on the basis of enabled or disabled sequence grouphopping, the base station apparatus comprising: means for transmitting,to the terminal apparatus, a cell-specific parameter used for enablingor disabling the sequence group hopping, and means for transmitting, tothe terminal apparatus, a user-equipment-specific parameter used fordisabling the sequence group hopping, wherein, in a case that a randomaccess response grant is used for scheduling for a transmission of aMessage 3 on the physical uplink shared channel in a random accessprocedure, the sequence group hopping is enabled or disabled on thebasis of the cell-specific parameter regardless of theuser-equipment-specific parameter.

(6) In addition, a base station apparatus that receives a demodulationreference signal associated with a physical uplink shared channel from aterminal apparatus, a sequence of the demodulation reference signalbeing generated on the basis of enabled or disabled sequence grouphopping, the base station apparatus comprising: means for transmitting,to the terminal apparatus, a cell-specific parameter used for enablingor disabling the sequence group hopping, and means for transmitting, tothe terminal apparatus, a user-equipment-specific parameter used fordisabling the sequence group hopping, wherein the sequence group hoppingis disabled on the basis of the user-equipment-specific parameterregardless of the cell-specific parameter, unless a downlink informationformat to which CRC parity bits scrambled by a temporary C-RNTI areattached or a random access response grant is used for scheduling for atransmission of a Message 3 on the physical uplink shared channels in arandom access procedure.

(7) In addition, an integrated circuit mounted on a terminal apparatusthat transmits a demodulation reference signal associated with aphysical uplink shared channel to a base station apparatus, theintegrated circuit causing the terminal apparatus causing the terminalapparatus to realize: a function of receiving, from the base stationapparatus, a cell-specific parameter used for enabling or disabling asequence group hopping, a function of receiving, from the base stationapparatus, a user-equipment-specific parameter used for disabling thesequence group hopping, a function of generating a sequence of thedemodulation reference signals on the basis of the enabled or disabledsequence group hopping, and a function of enabling or disabling, in acase that a transmission on the physical uplink shared channelcorresponding to a downlink control information format to which CRCparity bits scrambled by a temporary C-RNTI are attached is performed ina random access procedure, the sequence group hopping on the basis ofthe cell-specific parameter regardless of the user-equipment-specificparameter.

(8) In addition, an integrated circuit mounted on a terminal apparatusthat transmits a demodulation reference signal associated with aphysical uplink shared channel to a base station apparatus, theintegrated circuit causing the terminal apparatus causing the terminalapparatus to realize a function of receiving, from the base stationapparatus, a cell-specific parameter used for enabling or disabling asequence group hopping, a function of receiving, from the base stationapparatus, a user-equipment-specific parameter used for disabling thesequence group hopping, a function of generating a sequence of thedemodulation reference signal on the basis of the enabled or disabledsequence group hopping, and a function of enabling or disabling, in acase that a transmission of a Message 3 on the physical uplink sharedchannel corresponding to a random access response grant is performed ina random access procedure, the sequence group hopping on the basis ofthe cell-specific parameter regardless of the user-equipment-specificparameter.

(9) In addition, an integrated circuit mounted on a terminal apparatusthat transmits a demodulation reference signal associated with aphysical uplink shared channel to a base station apparatus, theintegrated circuit causing the terminal apparatus to realize a functionof receiving, from the base station apparatus, a cell-specific parameterused for enabling or disabling a sequence group hopping, a function ofreceiving, from the base station apparatus, a user-equipment-specificparameter used for disabling the sequence group hopping, a function ofgenerating a sequence of the demodulation reference signal on the basisof the enabled or disabled sequence group hopping, and a function ofdisabling the sequence group hopping on the basis of theuser-equipment-specific parameter regardless of the cell-specificparameter, unless a transmission of a Message 3 on the physical uplinkshared channel corresponding to a downlink control information format towhich CRC parity bits scrambled by a temporary C-RNTI are attached or onthe physical uplink shared channel corresponding to a random accessresponse grant in a random access procedure.

(10) An integrated circuit mounted on a base station apparatus thatreceives a demodulation reference signal associated with a physicaluplink shared channel from a terminal apparatus, a sequence of thedemodulation reference signal being generated on the basis of enabled ordisabled a sequence group hopping, the integrated circuit causing thebase station apparatus to realize a function of transmitting, to theterminal apparatus, a cell-specific parameter used for enabling ordisabling the sequence group hopping, a function of transmitting, to theterminal apparatus, a user-equipment-specific parameter used fordisabling the sequence group hopping, and a function of enabling ordisabling, in a case that a downlink control information format to whichCRC parity bits scrambled by a temporary C-RNTI are attached is used forscheduling for a transmission on the physical uplink shared channel in arandom access procedure, the sequence group hopping on the basis of thecell-specific parameter regardless of the user-equipment-specificparameter.

(11) An integrated circuit mounted on a base station apparatus thatreceives a demodulation reference signal associated with a physicaluplink shared channel from a terminal apparatus, a sequence of thedemodulation reference signal being generated on the basis of enabled ordisabled sequence group hopping, the integrated circuit causing the basestation apparatus to realize a function of transmitting, to the terminalapparatus, a cell-specific parameter used for enabling or disabling thesequence group hopping, a function of transmitting, to the terminalapparatus, a user-equipment-specific parameter used for disabling thesequence group hopping, a function of enabling or disabling, in a casethat a random access response grant is used for scheduling for atransmission of a Message 3 on the physical uplink shared channel, thesequence group hopping on the basis of the cell-specific parameterregardless of the user-equipment-specific parameter.

(12) In addition, an integrated circuit mounted on a base stationapparatus that receives a demodulation reference signal associated witha physical uplink shared channel from a terminal apparatus, a sequenceof the demodulation reference signal being generated on the basis ofenabled or disabled sequence group hopping, the integrated circuitcausing the base station apparatus to realize a function oftransmitting, to the terminal apparatus, a cell-specific parameter usedfor enabling or disabling the sequence group hopping, a function oftransmitting, to the terminal apparatus, a user-equipment-specificparameter used for disabling the sequence group hopping, and a functionof disabling the sequence group hopping on the basis of theuser-equipment-specific parameter regardless of the cell-specificparameter, unless a downlink information format to which CRC parity bitsscrambled by a temporary C-RNTI are attached or a random access responsegrant is used for scheduling for a transmission of a Message 3 on thephysical uplink shared channels in a random access procedure.Advantageous Effects of Invention

According to the present invention, a base station and a terminal candetermine parameters relating to an uplink reference signal andefficiently communicate with each other.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic block diagram illustrating the configuration of abase station according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram illustrating the configuration of aterminal according to the embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating an example of communicationaccording to the embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of downlink signals.

FIG. 5 is a flowchart illustrating the embodiment of the presentinvention.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention will be described hereinafter. Aradio communication system according to the embodiment of the presentinvention includes a primary base station (also referred to as a macrobase station, a first base station, a first communication apparatus, aserving base station, an anchor base station, or a primary cell) and asecondary base station (also referred to as an RRH, a pico base station,a femto base station, a Home eNodeB, a second base station apparatus, asecond communication apparatus, cooperative base stations, a cooperativebase station set, a cooperative base station, or a secondary cell) asbase station apparatuses (hereinafter also referred to as base stations,transmission apparatuses, cells, serving cells, transmission stations,transmission points, transmission antennas, transmission antenna ports,or eNodeBs). In addition, a mobile station apparatus (hereinafter alsoreferred to as a terminal, a terminal apparatus, a mobile terminal, areception apparatus, a reception point, a reception terminal, a thirdcommunication apparatus, reception antennas, reception antenna ports, oruser equipment (UE)) is also included.

Here, the secondary base station may be a plurality of secondary basestations. For example, the primary base station and the secondary basestation adopt heterogeneous network deployment, in which part or all ofthe coverage of the secondary base station is included in the coverageof the primary base station, in order to communicate with the terminal.

FIG. 1 is a schematic block diagram illustrating the configuration ofthe base station according to the embodiment of the present invention.Here, the base station illustrated in FIG. 1 may be a primary basestation or a secondary base station. The base station is configured byincluding a data control unit 101, a transmission data modulation unit102, a radio unit 103, a scheduling unit 104, a channel estimation unit105, a reception data demodulation unit 106, a data extraction unit 107,a higher layer 108, and an antenna 109. In addition, the radio unit 103,the scheduling unit 104, the channel estimation unit 105, the receptiondata demodulation unit 106, the data extraction unit 107, the higherlayer 108, and the antenna 109 configure a reception section. Inaddition, the data control unit 101, the transmission data modulationunit 102, the radio unit 103, the scheduling unit 104, the higher layer108, and the antenna 109 configure a transmission section. Here, eachcomponent configuring the base station will also be referred to as aunit.

The data control unit 101 receives transport channels from thescheduling unit 104. The data control unit 101 maps the transportchannels and signals generated in a physical layer in physical channelson the basis of scheduling information input from the scheduling unit104. Each piece of data mapped is output to the transmission datamodulation unit 102.

The transmission data modulation unit 102 modulates and encodestransmission data. The transmission data modulation unit 102 generatesthe transmission data by performing signal processing, such asmodulation, encoding, serial-to-parallel conversion of input signals, anIFFT (inverse Fast Fourier transform) process, and CP (cyclic prefix)insertion, on the data input from the data control unit 101 on the basisof the scheduling information from the scheduling unit 104 or the like.The transmission data modulation unit 102 then outputs the generatedtransmission data to the radio unit 103.

The radio unit 103 up-converts the transmission data input from thetransmission data modulation unit 102 into radio frequencies to generateradio signals and transmits the radio signals to the terminal throughthe antenna 109. In addition, the radio unit 103 receives radio signalsfrom the terminal through the antenna 109. The radio unit 103 thendown-converts the radio signals into baseband signals and outputsreception data to the channel estimation unit 105 and the reception datademodulation unit 106.

The scheduling unit 104, for example, maps logical channels andtransport channels and performs downlink and uplink scheduling. Thescheduling unit 104 includes interfaces between the scheduling unit 104and the antenna 109, the radio unit 103, the channel estimation unit105, the reception data demodulation unit 106, the data control unit101, the transmission data modulation unit 102, and the data extractionunit 107, in order to integrally control processing units in thephysical layers.

In addition, in the downlink scheduling, the scheduling unit 104performs transmission control in the transport channels and the physicalchannels and generates scheduling information on the basis of uplinkcontrol information received from the terminal, scheduling informationinput from the higher layer 108, and the like. The schedulinginformation used for the downlink scheduling is output to the datacontrol unit 101.

In addition, in the uplink scheduling, the scheduling unit 104 generatesscheduling information on the basis of an uplink channel state outputfrom the channel estimation unit 105, the scheduling information inputfrom the higher layer 108, and the like. The scheduling information usedfor the uplink scheduling is output to the data control unit 101.

In addition, the scheduling unit 104 maps downlink logical channelsinput from the higher layer 108 in the transport channels and outputsthe transport channels to the data control unit 101. In addition, thescheduling unit 104 maps uplink transport channels and control datainput from the data extraction unit 107 in uplink logical channels afterprocessing the uplink transport channels and the control data asnecessary, and then outputs the uplink logical channels to the higherlayer 108.

The channel estimation unit 105 estimates the uplink channel state onthe basis of uplink reference signals (for example, the demodulationreference signal) in order to demodulate uplink data, and then outputsthe uplink channel state to the reception data demodulation unit 106. Inaddition, the channel estimation unit 105 estimates the uplink channelstate on the basis of uplink reference signals (for example, a soundingreference signal) in order to perform the uplink scheduling, and thenoutputs the uplink channel state to the scheduling unit 104.

The reception data demodulation unit 106 demodulates reception data. Thereception data demodulation unit 106 performs a demodulation process onthe modulated data input from the radio unit 103 by performing signalprocessing, such as a DFT transform, subcarrier mapping, and an IFFTtransform, on the basis of a result of the estimation of the uplinkchannel state input from the channel estimation unit 105. The receptiondata demodulation unit 106 then outputs the modulated data to the dataextraction unit 107.

The data extraction unit 107 checks whether the reception data inputfrom the reception data demodulation unit 106 is correct and outputs aresult (for example, ACK or NACK) of the check to the scheduling unit104. In addition, the data extraction unit 107 divides the data inputfrom the reception data demodulation unit 106 into transport channelsand control data in the physical layer and outputs the transportchannels and the control data in the physical layer to the schedulingunit 104.

The higher layer 108 performs processing in a radio resource control(RRC) layer and processing in a MAC (media access control) layer. Thehigher layer 108 includes interfaces between the higher layer 108 andthe scheduling unit 104, the antenna 109, the radio unit 103, thechannel estimation unit 105, the reception data demodulation unit 106,the data control unit 101, the transmission data modulation unit 102,and the data extraction unit 107, in order to integrally controlprocessing units in a lower layer.

FIG. 2 is a schematic block diagram illustrating the configuration ofthe terminal according to the embodiment of the present invention. Theterminal is configured by including a data control unit 201, atransmission data modulation unit 202, a radio unit 203, a schedulingunit 204, a channel estimation unit 205, a reception data demodulationunit 206, a data extraction unit 207, a higher layer 208, and an antenna209. In addition, the data control unit 201, the transmission datamodulation unit 202, the radio unit 203, the scheduling unit 204, thehigher layer 208, and the antenna 209 configure a transmission section.In addition, the radio unit 203, the scheduling unit 204, the channelestimation unit 205, the reception data demodulation unit 206, the dataextraction unit 207, the higher layer 208, and the antenna 209 configurea reception section. Here, each component configuring the terminal willalso be referred to as a unit.

The data control unit 201 receives transport channels from thescheduling unit 204. In addition, the data control unit 201 maps thetransport channels and signals generated in the physical layer inphysical channels on the basis of scheduling information input from thescheduling unit 204. Each piece of data mapped is output to thetransmission data modulation unit 202.

The transmission data modulation unit 202 modulates and encodestransmission data. The transmission data modulation unit 202 generatesthe transmission data by performing signal processing, such asmodulation, encoding, serial-to-parallel conversion of input signals, anIFFT process, and CP insertion, on the data input from the data controlunit 201 and outputs the generated transmission data to the radio unit203.

The radio unit 203 up-converts the transmission data input from thetransmission data modulation unit 202 into radio frequencies to generateradio signals and transmits the radio signals to the terminal throughthe antenna 209. In addition, the radio unit 203 receives radio signalsfrom the base station through the antenna 209. The radio unit 203 thendown-converts the radio signals into baseband signals and outputsreception data to the channel estimation unit 205 and the reception datademodulation unit 206.

The scheduling unit 204, for example, maps logical channels andtransport channels and performs downlink and uplink scheduling. Thescheduling unit 204 includes interfaces between the scheduling unit 204and the antenna 209, the data control unit 201, the transmission datamodulation unit 202, the channel estimation unit 205, the reception datademodulation unit 206, the data extraction unit 207, and the radio unit203, in order to integrally control processing units in the physicallayer.

In addition, in the downlink scheduling, the scheduling unit 204performs reception control in the transport channels and the physicalchannels and generates scheduling information on the basis of downlinkcontrol information received from the base station, schedulinginformation input from the higher layer 208, and the like. Thescheduling information used for the downlink scheduling is output to thedata control unit 201.

In addition, in the uplink scheduling, the scheduling unit 204 performsa scheduling process for mapping the uplink logical channels input fromthe higher layer 208 in the transport channels and generates schedulinginformation used for the uplink scheduling on the basis of downlinkcontrol information received from the base station, the schedulinginformation input from the higher layer 208, and the like. Thescheduling information is output to the data control unit 201.

In addition, the scheduling unit 204 maps uplink logical channels inputfrom the higher layer 208 in the transport channels and outputs thetransport channels to the data control unit 201. In addition, thescheduling unit 204 outputs, to the data control unit 201, channel stateinformation input from the channel estimation unit 205 and a result of acheck of CRC (cyclic redundancy check) parity bits (also referred tosimply as a CRC) input from the data extraction unit 207.

In addition, the scheduling unit 204 determines parameters relating tothe uplink reference signal and generates the uplink reference signalusing the determined parameters. That is, the scheduling unit 204generates the uplink reference signal on the basis of enabled ordisabled sequence group hopping. In addition, the scheduling unit 204generates the uplink reference signal on the basis of enabled ordisabled sequence hopping.

The channel estimation unit 205 estimates a downlink channel state onthe basis of downlink reference signals (for example, the demodulationreference signal) in order to demodulate downlink data, and then outputsthe downlink channel state to the reception data demodulation unit 206.In addition, the reception data demodulation unit 206 demodulates thereception data input from the radio unit 203 and outputs the demodulatedreception data to the data extraction unit 207.

The data extraction unit 207 checks whether the reception data inputfrom the reception data demodulation unit 206 is correct and outputs aresult (for example, ACK or NACK) of the check to the scheduling unit204. In addition, the data extraction unit 207 divides the receptiondata input from the reception data demodulation unit 206 into transportchannels and control data in the physical layer and outputs thetransport channels and the control data in the physical layer to thescheduling unit 204.

The higher layer 208 performs processing in the radio resource controllayer and processing in the MAC layer. The higher layer 208 includesinterfaces between the higher layer 208 and the scheduling unit 204, theantenna 209, the data control unit 201, the transmission data modulationunit 202, the channel estimation unit 205, the reception datademodulation unit 206, the data extraction unit 207, and the radio unit203, in order to integrally control processing units in the lower layer.

FIG. 3 is a schematic diagram illustrating an example of communicationaccording to the embodiment of the present invention. In FIG. 3, aterminal 303 communicates with a primary base station 301 and/or asecond base station 302. In addition, a terminal 304 communicates withthe primary base station 301 and/or the secondary base station 302.

In FIG. 3, when transmitting an uplink signal to the base station, theterminal multiplexes the demodulation reference signal (DMRS), which isa signal known between the base station and the terminal, with theuplink signal and transmits the uplink signal. Here, the uplink signalincludes uplink data (an uplink shared channel (UL-SCH) or an uplinktransport block). In addition, the uplink signal includes uplink controlinformation (UCI). Here, the UL-SCH is a transport channel.

For example, the uplink data is mapped to a physical uplink sharedchannel (PUSCH). In addition, the uplink control information is mappedto the PUSCH or a physical uplink control channel (PUCCH). That is, inthe radio communication system, a demodulation reference signalassociated with transmission of the PUSCH (transmission on the PUSCH)are supported. The demodulation reference signal associated with thetransmission of the PUSCH will also be referred to as a first referencesignal.

In addition, a random access preamble is mapped to a physical randomaccess channel (PRACH). When transmitting the random access preamble tothe base station apparatus, the terminal transmits the random accesspreamble without multiplexing the demodulation reference signal.

That is, the first reference signal is used for demodulating the PUSCH.For example, the first reference signal is transmitted in a resourceblock (also referred to as a physical resource block, a physicalresource, or a resource) to which a corresponding PUSCH is mapped.

That is, the terminal 303 multiplexes the first reference signal withthe uplink signal to be transmitted to the primary base station 301 andtransmits the uplink signal to be through an uplink 305. In addition,the terminal 303 multiplexes the first reference signal with the uplinksignal transmitted to the secondary base station 302 and transmits theuplink signal through an uplink 306. In addition, the terminal 304multiplexes the first reference signal with the uplink signal to betransmitted to the primary base station 301 and transmits the uplinksignal through an uplink 307. In addition, the terminal 304 multiplexesthe first reference signal with the uplink signal to be transmitted tothe secondary base station 302 and transmits the uplink signal throughan uplink 308.

Here, if the first reference signal transmitted from the terminal 303and the first reference signal transmitted from the terminal 304 havethe same characteristics, interference undesirably occurs. For example,if interference has occurred between the first reference signalstransmitted from a plurality of terminals, an accuracy of estimating thestates of channels, which are used for demodulating the uplink signals,significantly decreases.

Therefore, it is desirable to orthogonalize the first reference signaltransmitted from the terminal 303 and the first reference signaltransmitted from the terminal 304 to each other. In addition, it isdesirable to randomize the interference between the first referencesignal transmitted from the terminal 303 and the first reference signaltransmitted from the terminal 304.

In addition, in FIG. 3, an aggregation of a plurality of serving cells(also referred to simply as cells) is supported in the downlink and theuplink (referred to as a carrier aggregation or a cell aggregation). Forexample, in each of the serving cells, a transmission bandwidth of up toone hundred and ten resource blocks may be used. Here, in the carrieraggregation, one of the serving cells is defined as a primary cell(Pcell). In addition, in the carrier aggregation, the serving cellsother than the primary cell are defined as secondary cells (Scells).

In addition, in the downlink, a carrier corresponding to the servingcell is defined as a downlink component carrier (DLCC). In addition, inthe downlink, a carrier corresponding to the primary cell is defined asa downlink primary component carrier (DLPCC). In addition, in thedownlink, a carrier corresponding to the secondary cell is defined as adownlink secondary component carrier (DLSCC).

Furthermore, in the uplink, a carrier corresponding to the serving cellis defined as an uplink component carrier (ULCC). In addition, in theuplink, a carrier corresponding to the primary cell is defined as anuplink primary component carrier (ULPCC). In addition, in the uplink, acarrier corresponding to the secondary cell is defined as an uplinksecondary component carrier (ULSCC).

That is, in the carrier aggregation, a plurality of component carriersare aggregated in order to support wide transmission bandwidths. Here,for example, the primary base station 301 may be regarded as a primarycell, and the secondary base station 302 may be regarded as a secondarycell (the base station configures to the terminal) (also referred to asHetNet deployment with a carrier aggregation).

FIG. 4 is a diagram illustrating an example of downlink signals. In FIG.4, a resource region for a physical downlink shared channel (PDSCH) towhich downlink data (a downlink shared channel (DL-SCH) or a downlinktransport block) is mapped are illustrated. Here, the DL-SCH is atransport channel.

In addition, a resource region for a physical downlink control channel(PDCCH) to which downlink control information (DCI) is mapped isillustrated. In addition, a resource region for an E-PDCCH (an enhancedPDCCH) to which downlink control information is mapped is illustrated.

For example, the PDCCH is mapped to first to third OFDM symbols in adownlink resource region. In addition, the E-PDCCH is mapped to fourthto twelfth OFDM symbols in the downlink resource region. In addition,the E-PDCCH is mapped to a first slot and a second slot in a subframe.In addition, the PDSCH and the E-PDCCH are subjected to FDM(frequency-division multiplexing). In the following description, theE-PDCCH is included in the PDCCH.

Here, the PDCCH is used for notifying (specifying) the downlink controlinformation to the terminal. In addition, a plurality of formats aredefined for the downlink control information transmitted on the PDCCH.Here, the formats of the downlink control information will also bereferred to as DCI formats.

For example, as DCI formats for the downlink, a DCI Format 1 and a DCIFormat 1A, which are used for scheduling of the PDSCH (transmission of aPDSCH codeword and a downlink transport block) in a cell, are defined.In addition, as another DCI format for the downlink, a DCI Format 2,which is used for scheduling of the PDSCH (transmission of up to twoPDSCH codewords and up to two downlink transport blocks) in a cell, isdefined.

For example, the DCI format for the downlink includes downlink controlinformation such as information regarding a resource assignment of thePDSCH and information regarding an MCS (modulation and coding scheme). ADCI format used for scheduling of the PDSCH will also be referred to asa downlink assignment hereinafter.

In addition, for example, as a DCI format for the uplink, a DCI Format0, which is used for scheduling of the PUSCH (transmission of a PUSCHcodeword and an uplink transport block) in a cell, is defined. Inaddition, as another DCI format for the uplink, a DCI Format 4, which isused for scheduling of the PUSCH (transmission of up to two PUSCHcodewords and up to two uplink transport blocks) in a cell, is defined.That is, the DCI Format 4 is used for scheduling of transmission(transmission mode) on the PUSCH using a plurality of antenna ports.

For example, the DCI format for the uplink includes downlink controlinformation such as information regarding a resource assignment of thePUSCH and information regarding the MCS (modulation and coding scheme).A DCI format used for scheduling of the PUSCH will also be referred toas an uplink grant hereinafter.

In addition, the PDSCH is used for transmitting downlink data.Furthermore, the PDSCH is used for notifying (specifying) a randomaccess response grant to the terminal. Here, the random access responsegrant is used for scheduling of the PUSCH. Here, the random accessresponse grant is indicated by a higher layer (for example, the MAClayer) to a physical layer.

For example, the base station transmits a random access response that istransmitted as Message 2 in a random access procedure while includingthe random access response grant in the random access response. Inaddition, the base station transmits the random access response grantcorresponding to Message 1 transmitted from the terminal in the randomaccess procedure. In addition, the base station transmits the randomaccess response grant for transmitting a Message 3 in the random accessprocedure. That is, the random access response grant may be used forscheduling of the PUSCH for transmitting the Message 3 in the randomaccess procedure.

In FIG. 4, the terminal monitors a set of PDCCH candidates. Here, thePDCCH candidates refer to candidates in which the PDCCHs may possibly beallocated and transmitted by the base station. In addition, the PDCCHcandidates are made up of one or a plurality of control channel elements(CCEs). In addition, the monitoring means that the terminal attempts todecode on each of PDCCHs in the set of PDCCH candidates according to allthe monitored DCI formats. Here, the set of PDCCH candidates monitoredby the terminal will also be referred to as a search space. That is, thesearch space refers to a set of resources that can be used by the basestation for transmitting the PDCCH.

Furthermore, in the resource region for the PDCCH, a common search space(CSS) and a UE-specific search space (USS; a terminal-specific(terminal-unique) search space) are configured (defined or set).

That is, in FIG. 4, the CSS and/or the USS are configured in theresource region for the PDCCH. In addition, the CSS and/or the USS areconfigured in the resource region for the E-PDCCH. The terminal monitorsthe PDCCH in the CSS and/or the USS in the resource region for the PDCCHand detects the PDCCH intended therefor. In addition, the terminalmonitors the E-PDCCH in the CSS and/or the USS in the resource regionfor the E-PDCCH and detects the E-PDCCH intended therefor.

Here, the CSS is used for transmitting downlink control informationintended for a plurality of terminals. That is, the CSS is defined by aresource common to the plurality of terminals. For example, the CSS isconfigured by CCEs having numbers predetermined between the base stationand the terminal. For example, the CSS is configured by CCEs havingindices of 0 to 15, respectively. Here, the CSS may be used fortransmitting downlink control information intended for a certainterminal. That is, the base station transmits, in the CSS, a DCI formatintended for a plurality of terminals and/or a DCI format intended for acertain terminal.

In addition, the USS is used for transmitting downlink controlinformation intended for a certain terminal. That is, the USS is definedby resources dedicated to the certain terminal. That is, the USS isindependently defined for each terminal. For example, the USS isconfigured by CCEs having numbers determined on the basis of a radionetwork temporary identifier (RNTI) assigned by the base station, a slotnumber in a radio frame, an aggregation level, or the like. Here, RNTIsinclude a C-RNTI (cell RNTI) and a temporary C-RNTI. That is, the basestation transmits, in the USS, a DCI Format intended for a certainterminal.

Here, an RNTI assigned by the base station to the terminal is used fortransmitting (transmission on the PDCCH) the downlink controlinformation. More specifically, a CRC (cyclic redundancy check paritybits (also referred to simply as a CRC)) generated on the basis of thedownlink control information (may be a DCI format, instead) are attachedto the downlink control information and, after the attachment, the CRCparity bits are scrambled by the RNTI.

The terminal attempts to decode the downlink control information withaccompanying the CRC parity bits scrambled by the RNTI and detects aPDCCH with which the CRC has been successful as a PDCCH intendedtherefor (also referred to as blind decoding). Here, the RNTI includesthe C-RNTI and the temporary C-RNTI. That is, the terminal decodes thePDCCH with the CRC scrambled by the C-RNTI. In addition, the terminaldecodes the PDCCH with the CRC scrambled by the temporary C-RNTI.

Here, the C-RNTI is a unique identification used for identifying an RRC(radio resource control) connection and scheduling. For example, theC-RNTI is used for dynamically scheduled unicast transmission.

In addition, the temporary C-RNTI is an identification used for therandom access procedure. Here, the base station transmits the temporaryC-RNTI while including the temporary C-RNTI in the random accessresponse. For example, the temporary C-RNTI is used, in the randomaccess procedure, for identifying a terminal that is performing therandom access procedure. In addition, the temporary C-RNTI is used for aretransmission of the Message 3 in the random access procedure. That is,in order for the terminal to retransmit the Message 3, the base stationtransmits the downlink control information on the PDCCH with the CRCscrambled by the temporary C-RNTI. That is, the terminal changes itsinterpretation of the downlink control information on the basis of whichRNTI has been used to scramble the CRC.

Here, for example, the terminal performs the random access procedure inorder to synchronize with the base station in a time domain. Inaddition, the terminal performs the random access procedure in order torealize initial connection establishment. In addition, the terminalperforms the random access procedure for a handover. In addition, theterminal performs the random access procedure in order to realizeconnection re-establishment. In addition, the terminal performs therandom access procedure in order to request resources of the UL-SCH.

An example of the random access procedure will be described hereinafter.

The terminal obtains SIB2 (System Information Block Type 2) transmittedfrom the base station using the PDSCH. SIB2 is a configuration(information) common to all terminals (may be a plurality of terminals)in a cell. The common configuration includes a configuration of thePRACH.

The terminal randomly selects a random access preamble number. Theterminal transmits the random access preamble (Message 1) having theselected number to the base station using the PRACH. The base stationreceives the random access preamble using the PRACH. The base stationestimates an uplink transmission timing using the random accesspreamble. The base station transmits the random access response (Message2) using the PDSCH. The random access response includes a plurality ofpieces of information for the random access preamble detected by thebase station. The plurality of pieces of information include the randomaccess preamble number, the temporary C-RNTI, a TA command (timingadvance command), and the random access response grant. The TA commandis used for instructing the terminal to adjust the uplink transmissiontiming. If the random access response includes the transmitted randomaccess preamble number, the terminal determines that the random accessresponse is intended therefor.

The terminal adjusts the uplink transmission timing on the basis of theTA command included in the random access response. The terminaltransmits the uplink data (the Message 3) using the PUSCH scheduled bythe random access response grant. The uplink data includes an identifier(information indicating an initial UE identity or information indicatingthe C-RNTI) for identifying the terminal. If the C-RNTI has been set,the terminal transmits the uplink data while including the informationindicating the C-RNTI in the uplink data. If the C-RNTI has not beenset, the terminal transmits the uplink data while including the initialUE identity in the uplink data. If S-TMSI (system architecture evolutiontemporary mobile subscriber identity) has been provided, the terminalsets the S-TMSI as the initial UE identity. In addition, if S-TMSI hasnot been provided, the terminal randomly selects a value from a range ofvalues of 0 to 240-1 and sets the selected value as the initial UEidentity. The S-TMSI is an identifier used for identifying the terminalin a tracking area.

If the base station has failed to decode the Message 3, the base stationcan transmit, using PDCCH with the CRC scrambled by the temporaryC-RNTI, downlink control information for instructing the terminal toretransmit the Message 3. Upon receiving, using the PDCCH with the CRCscrambled by the temporary-CRNTI, the downlink control information forinstructing the terminal to retransmit the Message 3, the terminalretransmits Message 3. On the other hand, if the base station has failedto decode the Message 3, the base station can transmit a NACK using aPHICH (a physical hybrid-ARQ indicator channel). Upon receiving the NACKusing the PHICH, the terminal retransmits the Message 3.

The base station can detect which terminal has transmitted the randomaccess preamble and the Message 3 by successfully decoding the Message 3and obtaining Message 3. That is, before successfully decoding theMessage 3, the base station cannot detect which terminal has transmittedthe random access preamble and the Message 3.

If the base station has received the initial UE identity, the basestation transmits a contention resolution identity (Message 4) havingthe same value as the received initial UE identity to the terminal usingthe PDCCH. If the value of the received contention resolution identityand the value of the transmitted initial UE identity match, the terminal(1) determines that contention resolution of the random access preamblehas been successful, (2) sets the value of the temporary C-RNTI to theC-RNTI, (3) discards the temporary C-RNTI, and (4) determines that therandom access procedure has been successfully completed.

If the base station has received the information indicating the C-RNTI,the base station transmits downlink control information (Message 4) tothe terminal using PDCCH with the CRC scrambled by the received C-RNTI.If the PDCCH with the CRC scrambled by the C-RNTI have been decoded, theterminal (1) determines that contention resolution of the random accesspreamble has been successful, (2) discards the temporary C-RNTI, and (3)determines that the random access procedure has been successfullycompleted.

If the resources of the PDSCH are scheduled by the downlink controlinformation transmitted on the PDCCH, the terminal receives downlinkdata on the scheduled PDSCH. On the other hand, if the resources of thePUSCH are scheduled by the downlink control information transmitted onthe PDCCH, the terminal transmits uplink data and/or uplink controlinformation on the scheduled PUSCHs. Here, the first reference signalsare multiplexed with the uplink data and/or the uplink controlinformation transmitted on the PUSCH.

In addition, the base station and the terminal transmit and receivesignals in the higher layer. For example, the base station and theterminal transmit and receive a radio resource control signal (alsoreferred to as RRC signaling, RRC message, or RRC information) in theRRC layer (Layer 3). Here, in the RRC layer, a dedicated signaltransmitted from the base station to a certain terminal will also bereferred to as a dedicated signal. That is, the base station transmits aconfiguration (information) specific (unique) to the certain terminalusing the dedicated signal.

In addition, the base station and the terminal transmit and receive aMAC control element in the MAC (media access control) layer (Layer 2).Here, the RRC signaling and/or the MAC control element will also bereferred to as higher layer signaling.

An example of a method for generating a reference signal sequencer^((α)) _(u, v) will be described hereinafter. Here, the referencesignal sequence is used for generating a sequence of the first referencesignal. For example, the reference signal sequence is defined by acyclic shift of a base sequence r^(−(α)) _(u, v) according to Expression1.

r _(u,v) ^((α)) =e ^(jαn) r _(u,v)(n), 0≤n≤M _(SC) ^(RS)   [Math. 1]

That is, the cyclic shift a is applied to the base sequence to generatethe reference signal sequence. In addition, multiple reference signalsequences are defined from a single reference sequence through differentvalues of the cyclic shift α. Here, M_(SC) ^(RS) denotes the length ofthe reference signal sequence, and, for example, M_(SC) ^(RS)=mN_(SC)^(RB). In addition, N_(SC) ^(RB) denotes the size of a resource block ina frequency domain and, for example, indicated by the number ofsubcarriers.

In addition, base sequences are divided into groups. That is, the basesequences are indicated by a group number (also referred to as asequence group number) u and a base sequence number v in thecorresponding group. For example, the base sequences are divided intothirty groups, and each group includes two base sequences. In addition,a sequence group hopping is applied to the thirty groups. In addition, asequence hopping is applied to the two base sequences.

Here, the sequence group number u and the base sequence number v maychange in time. In addition, the definition of the base sequence dependson the sequence length M_(SC) ^(RS), and, for example, the base sequenceis given by Expression 2 if M_(SC) ^(RS)≥3N_(SC) ^(RS).

r _(u,v)(n)=x _(q)(nmod N _(ZC) ^(RS)), 0≤n≤M _(SC) ^(MS)   [Math. 2]

Here, a q-th route Zadoff-Chu sequence x_(q)(m) is defined by Expression3.

$\begin{matrix}{{{x_{q}(m)} = e^{{- j}\; \frac{\pi \; {qm}{({m + 1})}}{N_{ZC}^{RS}}}},{0 \leq m \leq {N_{ZC}^{RS} - 1}}} & \lbrack {{Math}.\mspace{14mu} 3} \rbrack\end{matrix}$

Here, q is given by Expression 4.

q=└q+½┘+v·(−1)^(└2q┘)

q=N _(ZC) ^(RS)·(u+1)/31   [Math. 4]

Here, a length N_(ZC) ^(RS) of the Zadoff-Chu sequence is given by thelargest prime number that satisfies N_(ZC) ^(RS)<M_(SC) ^(RS).

In addition, the sequence group number u in slot n_(s) is defined by agroup hopping pattern f_(g)h(n_(s)) and a sequence shift pattern f_(ss)according to Expression 5.

u=(f _(gh)(n _(s))+f _(ss))mod30   [Math. 5]

Here, the base station can instruct the terminal to enable or disablethe sequence group hopping (also referred to simply as a group hopping).If instructed by the base station to enable the sequence group hopping,the terminal performs hopping on the groups of the reference signalsequences in each slot. That is, the terminal determines whether toperform hopping on the groups of the reference signal sequences in eachslot in accordance with enabling or disabling of the sequence grouphopping.

Here, for example, the group hopping pattern f_(gh)(n_(s)) is given byExpression 6.

$\begin{matrix}{{f_{gh}( n_{s} )} = \{ \begin{matrix}0 & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}} \\{( {\sum\limits_{i = 0}^{7}{{c( {{8n_{s}} + i} )} \cdot 2^{i}}} ){mod}\; 30} & {{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}}\end{matrix} } & \lbrack {{Math}.\mspace{14mu} 6} \rbrack\end{matrix}$

Here, a pseudo-random sequence c(i) is defined by Expression 7. Forexample, the pseudo-random sequence is defined by a Gold sequence havinga length of 31 and given by Expression 7.

c(n)(x ₁(n+N _(C))+x ₂(n+N _(C)))mod2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod2   [Math. 7]

Here, for example, N_(c)=1600. In addition, a first m sequence xi isinitialized by x₁(0)=1 and x₁(n)=0, where n=1, 2, . . . , and 30. Inaddition, a second m sequence x₂ is initialized by Expression 8.

c _(min)=Σ_(i=0) ³⁰ x ₂(i)·2^(i)   [Math. 8]

Here, c_(init) is defined by Expression 9. That is, the pseudo-randomsequence of the group hopping pattern f_(gh)(n_(s)) is initialized byExpression 9.

$\begin{matrix}{c_{init} = \lfloor \frac{N_{ID}^{cell}}{30} \rfloor} & \lbrack {{Math}.\mspace{14mu} 9} \rbrack\end{matrix}$

Here, a physical layer cell identity N_(ID) ^(cell) will be describedlater. In addition, a sequence shift pattern f_(ss) ^(PUSCH) for thePUSCH is given by Expression 10.

f_(ss) ^(PUCCH)=N_(ID) ^(cell) mod30

f _(ss) ^(PUSCH)=(f _(ss) ^(PUCCH)+Δ_(ss))mod30   [Math. 10]

Here, a parameter Δ_(ss) will be described later.

In addition, the base sequence number v in the base sequence group inthe slot n_(s) is defined by Expression 11. Here, the sequence hoppingmay be applied only to a reference signal sequence having a referencesignal length equal to or larger than 6N_(SC) ^(RB). That is, the basesequence number v of the reference signal sequence having the referencesignal length of smaller than 6N_(SC) ^(RB) is given by v=0.

$\begin{matrix}{v = \{ \begin{matrix}{c( n_{s} )} & \begin{matrix}{{if}\mspace{14mu} {group}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {disabled}\mspace{14mu} {and}} \\{{sequence}\mspace{14mu} {hopping}\mspace{14mu} {is}\mspace{14mu} {enabled}}\end{matrix} \\0 & {otherwise}\end{matrix} } & \lbrack {{Math}.\mspace{14mu} 11} \rbrack\end{matrix}$

Here, the base station can instruct the terminal to enable or disablethe sequence hopping. If instructed by the base station to enable thesequence hopping, the terminal performs hopping on the reference signalsequences in each group in each slot. That is, the terminal determineswhether to perform hopping on the reference signal sequences in eachslot in accordance with enabling or disabling of the sequence hopping.

Here, the pseudo-random sequence c(i) is defined by Expression 7 andExpression 8. In addition, c_(init) is defined by Expression 12. Thatis, the pseudo-random sequence of the reference sequence number v isinitialized by Expression 12.

$\begin{matrix}{c_{init} = {{\lfloor \frac{N_{ID}^{cell}}{30} \rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}} & \lbrack {{Math}.\mspace{14mu} 12} \rbrack\end{matrix}$

An example of a method for generating a sequence of the first referencesignals will be described hereinafter. That is, a method for generatingthe demodulation reference signal for the PUSCH will be described. Forexample, a demodulation reference signal sequence γ^((λ)) _(PUSCH)(·)for the PUSCH associated with layer λϵ{0, 1, . . . , υ−1} is defined byExpression 13.

r _(PUSCH) ^((λ))(m·M _(SC) ^(RS) +n)=w ^((λ))(m)r _(u,v) ^((α) ^(λ)⁾(n)   [Math. 13]

Here, υ denotes the number of transmission layers. In addition, forexample, υ is indicated by m=0 or 1. In addition, υ is indicated by n=0,. . . , and M_(SC) ^(RS)−1. In addition, M_(SC) ^(RS)=M_(SC) ^(PUSCH).Here, M_(SC) ^(PUSCH) denotes a bandwidth scheduled by the base stationfor uplink transmission (transmission on the PUSCH) and, for example, isindicated by the number of subcarriers. Furthermore, w^((λ))(m) denotesan orthogonal sequence.

In addition, a cyclic shift α_(λ) in a slot n_(s) is given byα_(λ)=2πn_(cs,λ). Here, n_(cs,λ) is expressed by Expression 14. That is,the cyclic shift applied to the first reference signal associated withthe PUSCH is defined by Expression 14.

n _(cs,λ)=(n _(DMRS) ⁽¹⁾ +n _(DMRS,λ) ⁽²⁾ +n _(PN)(n _(s)))mod12  [Math. 14]

Here, n⁽¹⁾ _(DMRS) is transmitted from the base station apparatus usingthe higher layer signal. In addition, n⁽²⁾ _(DMRS,λ) is indicated by thebase station apparatus using the DCI format. In addition, a quantityn_(PN(ns)) is given by Expression 15.

n _(PN)(n _(s))=Σ_(i=0) ⁷ c(8N _(symb) ^(UL) ·n _(s) +i)·2^(i)   [Math.15]

Here, the pseudo-random sequence c (i) is defined by Expression 7 andExpression 8. In addition, c_(init) is defined by Expression 16. Thatis, the cyclic shift applied to the first reference signal associatedwith the PUSCH is initialized by Expression 16.

$\begin{matrix}{c_{init} = {{\lfloor \frac{N_{ID}^{cell}}{30} \rfloor \cdot 2^{5}} + f_{ss}^{PUSCH}}} & \lbrack {{Math}.\mspace{14mu} 16} \rbrack\end{matrix}$

Here, in the above expression, N_(ID) ^(cell) denotes the physical layercell identity (also referred to as a physical layer cell identifier).That is, N_(ID) ^(cell) denotes identity specific (unique) to the cell(base station). That is, N_(ID) ^(cell) denotes a physical layeridentity of the cell. For example, N_(ID) ^(cell) may be N_(ID) ^(cell)corresponding to the primary cell.

For example, the terminal can detect N_(ID) ^(cell) usingsynchronization signals. In addition, the terminal can obtain N_(ID)^(cell) from information included in the higher layer signal (forexample, a handover command) transmitted from the base station.

In addition, in the above expression, for example, the parameter Δ_(ss)is indicated by Δ_(ss)ϵ{0, 1, . . . , 29}. Here, the parameter Δ_(ss) isa parameter specific to the cell (base station). For example, theterminal can receive the parameter Δ_(ss) using SIB2 (System InformationBlock Type 2). Here, SIB2 is a configuration (information) common to allterminals (may be a plurality of terminals) in a cell. That is, theparameter Δ_(ss) is specified for the terminal using the informationcommon to all the terminals in the cell.

FIG. 5 is a flowchart illustrating the embodiment. As described above,the base station can instruct the terminal to enable or disable thesequence group hopping of the reference signal sequence.

Here, as information for instructing the terminal to enable or disablethe sequence group hopping, a first parameter (also referred to asgroup-hopping-enabled) may be used. That is, the first parameter is usedfor determining whether the sequence group hopping is enabled. Inaddition, as information for instructing the terminal to disable thesequence group hopping, a second parameter (also referred to asdisable-sequence-hopping) may be used. That is, the second parameter isused for determining whether the sequence group hopping is disabled.Here, the second parameter cannot instruct the terminal to enable thesequence group hopping.

Here, the first parameter is configured in a cell-specific manner. Forexample, the first parameter is transmitted using SIB2 (SystemInformation Block Type 2). Here, SIB2 is a configuration (information)common to all the terminals (may be a plurality of terminals) in thecell. That is, the first parameter is a cell-specific parameter. Here,the first parameter will also be described as a cell-specific parameter.

On the other hand, the second parameter is configured in aterminal-specific (UE-specific) manner. For example, the secondparameter is configured using the dedicated signal. Alternatively, thesecond parameter may be indicated using downlink control informationincluded in a DCI format. That is, the second parameter is aterminal-specific parameter (a UE-specific parameter). The secondparameter will also be described as a UE-specific parameter hereinafter.

Here, for example, the base station can instruct the terminal to disablethe sequence group hopping by transmitting the dedicated signal whileincluding the second parameter in the dedicated signal. That is, thebase station can instruct the terminal to disable the sequence grouphopping by transmitting the second parameter to the terminal. If thededicated signal includes the second parameter, the terminal disablesthe sequence group hopping.

In addition, even though the sequence group hopping is enabled using thefirst parameter, the base station can disable the sequence group hoppingusing the second parameter. That is, for example, the second parameteris used for disabling the sequence group hopping for a certain terminaleven though the sequence group hopping is enabled in the cell-specificmanner.

A method for determining whether to enable or disable the sequence grouphopping by the terminal will be described with reference to FIG. 5. InFIG. 5, the terminal identifies the first parameter transmitted from thebase station (step 501). Here, in a case that the disabling of thesequence group hopping is configured (disable), the terminal disablesthe sequence group hopping and generates the first reference signal. Inaddition, the terminal transmits the generated first reference signal.

In addition, in a case that it is determined as a result of theidentification of the first parameter transmitted from the base stationthat the enabling of the sequence group hopping is configured (enable),the terminal identifies the second parameter. That is, for example, theterminal identifies whether the second parameter is configured (step502). Here, in a case that the second parameter is not configured (forexample, if the second parameter is not received using the dedicatedsignal) (NO), the terminal enables the sequence group hopping andgenerates the first reference signal. In addition, the terminaltransmits the generated first reference signal.

Furthermore, in a case that the second parameter is configured (forexample, in a case that the second parameter is received using thededicated signal) (YES), the terminal identifies the DCI format (step503). That is, the terminal identifies the DCI format used forscheduling of the corresponding PUSCH transmission.

Here, in a case that the DCI format is not identified (detected orreceived), the terminal enables the sequence group hopping and generatesthe first reference signal. In addition, the terminal transmits thegenerated first reference signal.

Here, in a case that the DCI Format 4 is identified (detected orreceived) (DCI FORMAT 4), the terminal disables the sequence grouphopping and generates the first reference signal. In addition, theterminal transmits the generated first reference signal. Here, forexample, the DCI Format 4 is transmitted only in the USS. That is, in acase that the DCI format transmitted only in the USS is identified, theterminal disables the sequence group hopping and generates the firstreference signal.

On the other hand, in a case that the DCI Format 0 is identified(detected or received) (DCI FORMAT 0), the terminal identifies the RNTIby which the CRC is scrambled (step 504). Here, for example, the DCIFormat 0 is transmitted in the CSS and/or the USS. That is, in a casethat the DCI format that is possible to be transmitted in the CSS isidentified, the terminal identifies the RNTI. The DCI Format 0 will alsobe described as a predetermined downlink information format hereinafter.In addition, the DCI Format 4 will also be described as a downlinkinformation format other than the predetermined downlink informationformat.

Here, the DCI format received by the terminal refers to a DCI formatincluding most recent uplink-related DCI for a transport blockassociated with the corresponding PUSCH transmission.

In addition, in the case that the DCI format is not received, theterminal does not receive any DCI format for the transport blockassociated with the corresponding PUSCH transmission. For example, in acase that an initial transmission of the transport block scheduled bythe random access response grant is performed, there is no DCI formatfor the transport block transmitted using the PUSCH. In addition, in acase that the DCI format indicating a retransmission of the transportblock is not received and the transport block is retransmitted inaccordance with NACK received using the PHICH (the physical hybrid-ARQindicator channel), there is no DCI format for the transport blocktransmitted using the PUSCH.

Here, the PHICH is a channel used for transmitting informationindicating ACK/NACK (also referred to as ACK/NACK in HARQ) in responseto uplink data. The base station transmits, using the PHICH, theinformation indicating ACK/NACK in response to the uplink datatransmitted from the terminal.

In addition, in a case that the CRC is scrambled by the C-RNTI (C-RNTI),the terminal disables the sequence group hopping and generates the firstreference signal. In addition, the terminal transmits the generatedfirst reference signal. Here, in a case that the CRC is scrambled by thetemporary C-RNTI (TEMPORARY C-RNTI), the terminal enables the sequencegroup hopping and generates the first reference signal. In addition, theterminal transmits the generated first reference signal.

Here, the RNTI by which the CRC is scrambled refers to RNTI used fortransmitting the most recent uplink-related DCI for the transport blockassociated with the corresponding PUSCH transmission.

That is, the terminal can enable or disable the sequence group hoppingon the basis of the cell-specific parameter, the terminal-specificparameter, the DCI format, and/or the RNTI.

That is, the terminal determines whether to follow the cell-specificparameter or the terminal-specific parameter on the basis of the DCIformat and/or the RNTI by which the CRC is scrambled.

That is, even though the sequence group hopping is disabled in theterminal-specific manner, the first parameter may be used for enablingor disabling the sequence group hopping in a case that the PUSCH for thetransport block is scheduled by the random access response grant and theuplink grant for the transport block is not received.

In addition, even though the sequence group hopping is disabled in theterminal-specific manner, the first parameter may be used for enablingor disabling the sequence group hopping in a case that the temporaryC-RNTI is used for transmitting the most recent uplink-related DCI forthe transport block associated with the corresponding PUSCHtransmission.

That is, even though the sequence group hopping is disabled in theterminal-specific manner, the first parameter may be used for enablingor disabling the sequence group hopping in a case that a transmission ofthe Message 3 is performed.

In addition, even though the sequence group hopping is enabled in thecell-specific manner, the second parameter may be used for disabling thesequence group hopping for a certain terminal in a case that the C-RNTIis used for transmitting the most recent uplink-related DCI for thetransport block associated with the corresponding PUSCH transmission.That is, the second parameter may be used for disabling the sequencegroup hopping for a certain terminal in a case that a transmission ofthe uplink data other than the Message 3 is performed.

In addition, the base station can instruct the terminal to enable ordisable the sequence hopping of the reference signal sequences.

Here, as the information for instructing the terminal to enable ordisable the sequence hopping, a third parameter (also referred to assequence-hopping-enabled) may be used. That is, the third parameter isused for determining whether to enable the sequence hopping.

In addition, as the information for instructing the terminal to disablethe sequence hopping, the above-described second parameter(disable-sequence-hopping) may be used. That is, the second parameter isused for determining whether to disable the sequence hopping. That is,the second parameter is used for determining whether to disable thesequence group hopping and the sequence hopping. Here, the secondparameter cannot instruct the terminal to enable the sequence hopping.In addition, the sequence hopping can be enabled using the secondparameter only if the sequence group hopping is disabled.

Here, the third parameter is configured in the cell-specific manner. Forexample, the third parameter is transmitted using SIB2 (SystemInformation Block Type 2). That is, the third parameter is thecell-specific parameter.

Here, even though the sequence hopping is enabled using the thirdparameter, the base station can disable the sequence hopping using thesecond parameter. That is, the second parameter may be used fordisabling the sequence hopping for a certain terminal even though thesequence hopping is enabled in the cell-specific manner.

A method for determining whether to enable or disable the sequencehopping using the terminal will be described with reference to FIG. 5.In FIG. 5, the terminal identifies the third parameter transmitted fromthe base station (step 501). Here, in a case that the disabling of thesequence group hopping is configured (disable), the terminal disablesthe sequence group hopping and generates the first reference signal. Inaddition, the terminal transmits the generated first reference signal.

In addition, in a case that it is determined as a result of theidentification of the first parameter transmitted from the base stationthat the enabling of the sequence group hopping is configured (enable),the terminal identifies the second parameter. That is, for example, theterminal identifies whether the second parameter is configured (step502). Here, in a case that the second parameter is not configured (forexample, in a case that the second parameter is not received using thededicated signal) (NO), the terminal enables the sequence hopping andgenerates the first reference signal. In addition, the terminaltransmits the generated first reference signal.

Furthermore, in a case that the second parameter is configured (forexample, in a case that the second parameter is received using dedicatedsignal) (YES), the terminal identifies the DCI format (step 503). Thatis, the terminal identifies the DCI format used for scheduling of thecorresponding PUSCH transmission.

Here, in a case that the DCI format is not identified (detected orreceived), the terminal enables the sequence hopping and generates thefirst reference signal. In addition, the terminal transmits thegenerated first reference signal.

Here, in a case that the DCI Format 4 is identified (detected orreceived) (DCI FORMAT 4), the terminal disables the sequence hopping andgenerates the first reference signal. In addition, the terminaltransmits the generated first reference signal. Here, for example, theDCI Format 4 is transmitted only in the USS. That is, in a case that theDCI format transmitted only in the USS is identified, the terminaldisables the sequence hopping and generates the first reference signal.

On the other hand, in a case that the DCI Format 0 is identified(detected or received) (DCI FORMAT 0), the terminal identifies the RNTIby which the CRC is scrambled (step 504). Here, for example, the DCIFormat 0 is transmitted in the CSS and/or the USS. That is, in a casethat the DCI format that is possible to be transmitted in the CSS isidentified, the terminal identifies the RNTI. Here, the DCI Format 0will also be described as a predetermined downlink information format.In addition, the DCI Format 4 will also be described as a downlinkinformation format other than the predetermined downlink informationformat.

Here, the DCI format received by the terminal refers to a DCI formatincluding the most recent uplink-related DCI for the transport blockassociated with the corresponding PUSCH transmission.

In addition, in the case that the DCI format, the terminal does notreceive any DCI format for the transport block associated with thecorresponding PUSCH transmission. For example, in a case that an initialtransmission of the transport block scheduled by the random accessresponse grant is performed, there is no DCI format for the transportblock transmitted using the PUSCH. In addition, in a case that the DCIformat indicating a retransmission of the transport block is notreceived and the transport block is retransmitted in accordance withNACK received using PHICH, there is no DCI format for the transportblock transmitted using the PUSCH.

In addition, in a case that the CRC is scrambled by the C-RNTI (C-RNTI),the terminal disables the sequence hopping and generates the firstreference signal. In addition, the terminal transmits the generatedfirst reference signal. Here, in a case that the CRC is scrambled by thetemporary C-RNTI (TEMPORARY C-RNTI), the terminal enables the sequencehopping and generates the first reference signal. In addition, theterminal transmits the generated first reference signal.

Here, the RNTI by which the CRC is scrambled refers to RNTI used fortransmitting the most recent uplink-related DCI for the transport blockassociated with the corresponding PUSCH transmission.

That is, the terminal can enable or disable the sequence group hoppingon the basis of the cell-specific parameter, the terminal-specificparameter, the DCI format, and/or the RNTI.

That is, the terminal determines whether to follow the cell-specificparameter or the terminal-specific parameter on the basis of the DCIformat and/or the RNTI by which the CRC is scrambled.

That is, even though the sequence hopping is disabled in theterminal-specific manner, the third parameter may be used for enablingor disabling the sequence hopping in a case that the PUSCH for thetransport block is scheduled by the random access response grant and theuplink grant for the transport block is not received.

In addition, even though the sequence hopping is disabled in theterminal-specific manner, the third parameter may be used for enablingor disabling the sequence hopping in a case that the temporary C-RNTI isused for transmitting the most recent uplink-related DCI for thetransport block associated with the corresponding PUSCH transmission.

That is, even though the sequence hopping is disabled in theterminal-specific manner, the third parameter may be used for enablingor disabling the sequence hopping in a case that a transmission of theMessage 3 is performed.

In addition, even though the sequence hopping is enabled in thecell-specific manner, the second parameter may be used for disabling thesequence hopping for a certain terminal in a case that the C-RNTI isused for transmitting the most recent uplink-related DCI for thetransport block associated with the corresponding PUSCH transmission.That is, the second parameter may be used for disabling the sequencehopping for a certain terminal in a case that a transmission of theuplink data other than the Message 3 is performed.

Using the above-described method, the terminal determines whether toenable or disable the sequence group hopping and the sequence hopping onthe basis of the cell-specific first parameter and the cell-specificthird parameter in the case that the Message 3 is to be transmitted.That is, even though the sequence group hopping and the sequence hoppingare disabled by the terminal-specific second parameter, in case oftransmitting the Message 3, the terminal determines whether to enable ordisable the sequence group hopping and the second hopping on the basisof the cell-specific first parameter and the cell-specific thirdparameter.

In addition, in case of transmitting the uplink data other than theMessage 3, the terminal determines whether the sequence group hoppingand the sequence hopping are disabled on the basis of theterminal-specific second parameter. As a result, even though the basestation does not identify which terminal has transmitted the Message 3,the base station can determine whether the terminal has disabled thesequence group hopping or the sequence hopping on the basis of thecell-specific first parameter and the cell-specific second parameter.Therefore, the base station can correctly receive Message 3.

The above-described method enables, for example, transmission andreception of the uplink reference signal while switching the sequencesmore elastically. In addition, the above-described method enablestransmission and reception of the uplink reference signal whileswitching the sequences more dynamically.

When the base station switches the sequence group hopping and/or thesequence hopping in the above-described manner, it is possible toelastically control transmission of the uplink reference signalstransmitted by a plurality of terminals.

Programs operating on a primary base station, a secondary base station,and a terminal according to the present invention are programs (programsthat causes computers to function) that control CPUs or the like in sucha way as to realize the functions of the above embodiment of the presentinvention. Information handled by these apparatuses is temporarilyaccumulated in RAMs during processing, and then stored in various ROMsor HDDs and read, corrected, and written by the CPUs as necessary. Asrecording media that store the programs, any of semiconductor media (forexample, ROMs, nonvolatile memory cards, and the like), opticalrecording media (for example, DVDs, MOs, MDs, CDs, BDs, and the like),magnetic recording media (for example, magnetic tapes, flexible disks,and the like), and the like may be used. In addition, the functions ofthe above-described embodiment may be realized not only by executing theloaded programs but also by performing processing in combination withoperating systems, other application programs, or the like on the basisof instructions from the programs.

In addition, when the programs are to be distributed to the market, theprograms may be stored in portable recording media and distributed ortransferred to a server computer connected through a network such as theInternet. In this case, a storage device of the server computer is alsoincluded in the present invention. Alternatively, part or all of theprimary base station, the secondary base station, and the terminal inthe above-described embodiment may be realized as LSI, which istypically integrated circuits. Here, each function block of the primarybase station, the secondary base station, and the terminal may beindividually realized as a chip, or part or all of the function blocksmay be integrated and realized as a chip. In addition, a method forrealizing the function blocks as integrated circuits is not limited tothe LSI, but may be realized by dedicated circuits or general-purposeprocessors. In addition, if a technology for realizing the functionblocks as integrated circuits that replaces the LSI has been developedas a result of the evolution of semiconductor technologies, integratedcircuits realized by the technology may be used.

As described above, the embodiment may adopt the following modes. Thatis, a mobile station apparatus that communicates with a base stationapparatus receives, from the base station apparatus, a cell-specificparameter and a user-equipment-specific parameter for indicatingenabling or disabling of a sequence group hopping, and transmits, to thebase station apparatus, a reference signal generated by enabling thesequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and there is no downlink controlinformation format for a transport block to be transmitted.

In addition, a mobile station apparatus that communicates with a basestation apparatus receives, from the base station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, andtransmits, to the base station apparatus, a reference signal generatedby enabling the sequence hopping in a case that enabling is indicated bythe cell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and a predetermined downlink controlinformation format with a CRC scrambled by a temporary C-RNTI isreceived.

In addition, a base station apparatus that communicates with a mobilestation apparatus transmits, to the mobile station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, andreceives, from the mobile station apparatus, a reference signalgenerated by enabling the sequence hopping in a case that enabling isindicated by the cell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and there is no downlink controlinformation format for a transport block to be transmitted by the mobilestation apparatus.

In addition, a base station apparatus that communicates with a mobilestation apparatus transmits, to the mobile station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, andreceives, from the mobile station apparatus, a reference signalgenerated by enabling the sequence hopping in a case that enabling isindicated by the cell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and a predetermined downlink controlinformation format with a CRC scrambled by a temporary C-RNTI istransmitted.

In addition, in a communication method used by a mobile stationapparatus that communicates with a base station apparatus, the mobilestation apparatus receives, from the base station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, andtransmits, to the base station apparatus, a reference signal generatedby enabling the sequence group hopping in a case that enabling isindicated by the cell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and there is no downlink controlinformation format for a transport block to be transmitted.

In addition, in a communication method used by a mobile stationapparatus that communicates with a base station apparatus, the mobilestation apparatus receives, from the base station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, andtransmits, to the base station apparatus, a reference signal by enablingthe sequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and a predetermined downlink controlinformation format with a CRC scrambled by a temporary C-RNTI isreceived.

In addition, in a communication method used by a base station apparatusthat communicates with a mobile station apparatus, the base stationapparatus transmits, to the mobile station apparatus, a cell-specificparameter and a user-equipment-specific parameter for indicatingenabling or disabling of a sequence group hopping, and receives, fromthe mobile station apparatus, a reference signal generated by enablingthe sequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and there is no downlink controlinformation format for a transport block to be transmitted by the mobilestation apparatus.

In addition, in a communication method used by a base station apparatusthat communicates with a mobile station apparatus, the base stationapparatus transmits, to the mobile station apparatus, a cell-specificparameter and a user-equipment-specific parameter for indicatingenabling or disabling of a sequence group hopping, and receives, fromthe mobile station apparatus, a reference signal generated by enablingthe sequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and a predetermined downlink controlinformation format with a CRC scrambled by a temporary C-RNTI istransmitted.

In addition, an integrated circuit mounted on a mobile station apparatusthat communicates with a base station apparatus causes the mobilestation apparatus to realize a function of receiving, from the basestation apparatus, a cell-specific parameter and auser-equipment-specific parameter for indicating enabling or disablingof a sequence group hopping, and a function of transmitting, to the basestation apparatus, a reference signal generated by enabling the sequencegroup hopping in a case that enabling is indicated by the cell-specificparameter, disabling is indicated by the user-equipment-specificparameter, and there is no downlink control information format for atransport block to be transmitted.

In addition, an integrated circuit mounted on a mobile station apparatusthat communicates with a base station apparatus causes the mobilestation apparatus to realize a function of receiving, from the basestation apparatus, a cell-specific parameter and auser-equipment-specific parameter for indicating enabling or disablingof a sequence group hopping, and a function of transmitting, to the basestation apparatus, a reference signal generated by enabling the sequencegroup hopping in a case that enabling is indicated by the cell-specificparameter, disabling is indicated by the user-equipment-specificparameter, and a predetermined downlink control information format witha CRC scrambled by a temporary C-RNTI is received.

In addition, an integrated circuit mounted on a base station apparatusthat communicates with a mobile station apparatus causes the basestation apparatus to realize a function of transmitting, to the basestation apparatus, a cell-specific parameter and auser-equipment-specific parameter for indicating enabling or disablingof a sequence group hopping, and a function of receiving, from themobile station apparatus, a reference signal generated by enabling thesequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and there is no downlink controlinformation format for a transport block to be transmitted by the mobilestation apparatus.

In addition, an integrated circuit mounted on a base station apparatusthat communicates with a mobile station apparatus causes the basestation apparatus to realize a function of transmitting, to the mobilestation apparatus, a cell-specific parameter and auser-equipment-specific parameter for indicating enabling or disablingof a sequence group hopping, and a function of receiving, from themobile station apparatus, a reference signal generated by enabling thesequence group hopping in a case that enabling is indicated by thecell-specific parameter, disabling is indicated by theuser-equipment-specific parameter, and a predetermined downlink controlinformation format with a CRC scrambled by a temporary C-RNTI istransmitted.

In addition, in a radio communication system in which a base stationapparatus and a mobile station apparatus communicate with each other,the base station apparatus transmits, to the mobile station apparatus, acell-specific parameter and a user-equipment-specific parameter forindicating enabling or disabling of a sequence group hopping, the mobilestation apparatus transmits, to the base station apparatus, a referencesignal generated by enabling the sequence group hopping in a case thatenabling is indicated by the cell-specific parameter, disabling isindicated by the user-equipment-specific parameter, and a predetermineddownlink control information format with a CRC scrambled by a temporaryC-RNTI is received.

Although the embodiment of the present invention has been described indetail with reference to the drawings, specific configurations are notlimited to this embodiment, and design changes and the like that do notdeviate from the scope of the present invention are also included. Inaddition, the present invention may be modified in various ways withinthe range defined in the claims, and embodiments obtained byappropriately combining technical means disclosed in differentembodiments are also included in the technical scope of the presentinvention. In addition, configurations obtained by replacing elementsthat have been described in the embodiment and that produce the sameadvantageous effects are also included.

INDUSTRIAL APPLICABILITY

The present invention may be desirably applied to a mobile stationapparatus, a base station apparatus, a communication method, a radiocommunication system, and an integrated circuit.

REFERENCE SIGNS LIST

100 base station

101 data control unit

102 transmission data modulation unit

103 radio unit

104 scheduling unit

105 channel estimation unit

106 reception data demodulation unit

107 data extraction unit

108 higher layer

109 antenna

200 terminal

201 data control unit

202 transmission data modulation unit

203 radio unit

204 scheduling unit

205 channel estimation unit

206 reception data demodulation unit

207 data extraction unit

208 higher layer

209 antenna

301 primary base station

302 secondary base station

303, 304 terminal

305, 306, 307, 308 uplink

1. (canceled)
 2. A user equipment comprising: transmitting circuitryconfigured to transmit, to a base station apparatus, a demodulationreference signal associated with transmission of a physical uplinkshared channel, a demodulation reference signal sequence of thedemodulation reference signal being generated based on whether asequence group hopping is enabled or disabled, wherein the sequencegroup hopping is enabled or disabled based on a first parameter, asecond parameter, and whether or not the transmission of the physicaluplink shared channel is in a four steps random access procedure.
 3. Abase station apparatus comprising: receiving circuitry configured toreceive, from a user equipment, a demodulation reference signalassociated with transmission of a physical uplink shared channel, ademodulation reference signal sequence of the demodulation referencesignal being generated based on whether a sequence group hopping isenabled or disabled, wherein the sequence group hopping is enabled ordisabled based on a first parameter, a second parameter, and whether ornot the transmission of the physical uplink shared channel is in a foursteps random access procedure.
 4. A communication method of a userequipment comprising: transmitting, to a base station apparatus, ademodulation reference signal associated with transmission of a physicaluplink shared channel, a demodulation reference signal sequence of thedemodulation reference signal being generated based on whether asequence group hopping is enabled or disabled, wherein the sequencegroup hopping is enabled or disabled based on a first parameter, asecond parameter, and whether or not the transmission of the physicaluplink shared channel is in a four steps random access procedure.
 5. Acommunication method of a base station apparatus comprising: receiving,from a user equipment, a demodulation reference signal associated withtransmission of a physical uplink shared channel, a demodulationreference signal sequence of the demodulation reference signal beinggenerated based on whether a sequence group hopping is enabled ordisabled, wherein the sequence group hopping is enabled or disabledbased on a first parameter, a second parameter, and whether or not thetransmission of the physical uplink shared channel is in a four stepsrandom access procedure.